There is a sort of "aerosol-pssssss" sound on all of my Palm devices when I administer the meds. There is a way to tell that the meds have been administered, though, even if you can't hear the sound. You'll notice that the syringe is full when it's in the tray at the top of the screen. If you "miss" your pet when you administer it, it stays full. When properly administered, the syringe will empty and lose the color that the meds give it when it's full. Also, your pet will
usually lie down immediately and go to sleep when you give it the meds (sometimes right on top of the syringe, which will frustrate your attempt at visual confirmation). I hope that helps, because it's no fun to turn on the game and discover that you've killed your pet (or, even worse, your little boy's pet).